A more testable linux version detector

.docker/Dockerfile-amazon-2

@@ -0,0 +1,6 @@
+FROM amazonlinux:2
+
+RUN yum update -y && \
+    yum install -y ruby libjpeg-turbo libpng libXrender fontconfig libXext openssl
+
+CMD /root/wkhtmltopdf_binary_gem/bin/wkhtmltopdf --version

.docker/Dockerfile-amazon-2022

@@ -0,0 +1,6 @@
+FROM amazonlinux:2022
+
+RUN yum update -y && \
+    yum install -y ruby libjpeg-turbo libpng libXrender fontconfig libXext openssl
+
+CMD /root/wkhtmltopdf_binary_gem/bin/wkhtmltopdf --version

Rakefile

@@ -12,5 +12,10 @@ Rake::TestTask.new do |t|
   t.libs << 'test'
 end
 
+Rake::TestTask.new do |t|
+  t.name = 'unit'
+  t.pattern = 'test/wkhtmltopdf/**/*.rb'
+end
+
 desc 'Run tests'
-task default: :test
+task default: [:unit, :test]

bin/wkhtmltopdf

@@ -10,44 +10,18 @@
 require 'rbconfig'
 require 'zlib'
 
+$LOAD_PATH.unshift File.expand_path('../lib/', File.dirname(__FILE__))
+require 'wkhtmltopdf/linux_os_detector'
+
 suffix = case RbConfig::CONFIG['host_os']
          when /linux/
-           os = `. /etc/os-release 2> /dev/null && echo ${ID}_${VERSION_ID}`.strip
-
-           os = 'ubuntu_16.04' if os.start_with?('ubuntu_16.') ||
-                                  os.start_with?('ubuntu_17.') ||
-                                  os.start_with?('linuxmint_18.')
-
-           os = 'ubuntu_18.04' if os.start_with?('ubuntu_18.') ||
-                                  os.start_with?('ubuntu_19.') ||
-                                  os.start_with?('elementary') ||
-                                  os.start_with?('linuxmint_19.') ||
-                                  os.start_with?('pop') ||
-                                  os.start_with?('zorin')
-
-           os = 'ubuntu_20.04' if os.start_with?('ubuntu_20.') ||
-                                  os.start_with?('ubuntu_21.') ||
-                                  os.start_with?('linuxmint_20.')
-
-           os = 'ubuntu_22.04' if os.start_with?('ubuntu_22.') ||
-                                  os.start_with?('linuxmint_21.')
-
-           os = 'centos_6' if (os.start_with?('amzn_') && os != 'amzn_2') ||
-                              (os.empty? && File.read('/etc/centos-release').start_with?('CentOS release 6'))
-
-           os = 'centos_7' if (os.start_with?('amzn_2') && !os.start_with?('amzn_20')) ||
-                              os.start_with?('rhel_7.')
-
-           os = 'centos_8' if os.start_with?('rocky_8') || os.start_with?('rhel_8.')
-
-           os_based_on_debian_9 = os.start_with?('debian_9') ||
-                                  os.start_with?('deepin')
-           os = 'debian_9' if os_based_on_debian_9
-
-           os = 'debian_10' if !os_based_on_debian_9 && os.start_with?('debian')
+           id, version = if File.exist?('/etc/os-release')
+                          `. /etc/os-release 2> /dev/null && echo ${ID} ${VERSION_ID}`.strip.split
+                         else
+                          ['', '']
+                         end
 
-           os = 'archlinux' if os.start_with?('arch_') ||
-                               os.start_with?('manjaro_')
+           os = Wkhtmltopdf::LinuxOsDetector.new(id, version).os
 
            architecture = RbConfig::CONFIG['host_cpu'] == 'x86_64' ? 'amd64' : 'i386'
 

docker-compose.yml

@@ -77,3 +77,17 @@ services:
       dockerfile: .docker/Dockerfile-archlinux
     volumes:
       - .:/root/wkhtmltopdf_binary_gem
+
+  amazon_2:
+    build:
+      context: .
+      dockerfile: .docker/Dockerfile-amazon-2
+    volumes:
+      - .:/root/wkhtmltopdf_binary_gem
+
+  amazon_2022:
+    build:
+      context: .
+      dockerfile: .docker/Dockerfile-amazon-2022
+    volumes:
+      - .:/root/wkhtmltopdf_binary_gem

lib/wkhtmltopdf/linux_os_detector.rb

@@ -0,0 +1,101 @@
+module Wkhtmltopdf
+  class LinuxOsDetector
+
+    def initialize(id, version)
+      raise ArgumentError if id.nil? || version.nil?
+
+      @id = id
+      @version = version
+      @extras = {}
+    end
+
+    def os
+      gather_extra_information
+
+      return special_cases if id.empty?
+      return send(id) if self.respond_to?(id, true)
+      "#{id}_#{version}"
+    end
+
+    private
+
+    def gather_extra_information
+      @extras['centos-release'] = File.read('/etc/centos-release') if File.exist?('/etc/centos-release')
+    end
+
+    def special_cases
+      if @extras.key?('centos-release') && @extras['centos-release'].start_with?('CentOS release 6')
+        'centos_6'
+      end
+    end
+
+    def linuxmint
+      case version
+      when /^18/; 'ubuntu_16.04'
+      when /^19/; 'ubuntu_18.04'
+      when /^20/; 'ubuntu_20.04'
+      when /^21/; 'ubuntu_22.04'
+      end
+    end
+
+    def ubuntu
+      case version
+      when /^(16|17)/; 'ubuntu_16.04'
+      when /^(18|19)/; 'ubuntu_18.04'
+      when /^(20|21)/; 'ubuntu_20.04'
+      when /^(22)/; 'ubuntu_22.04'
+      end
+    end
+
+    def debian
+      case version
+      when '9'; 'debian_9'
+      else; 'debian_10'
+      end
+    end
+
+    def deepin
+      'debian_9'
+    end
+
+    def amzn
+      case version
+      when '2'; 'centos_7'
+      when /^2018/; 'centos_6'
+      when /^2022/; 'centos_7'
+      end
+    end
+
+    def rhel
+      case version
+      when /^8\./; 'centos_8'
+      end
+    end
+
+    def rocky
+      'centos_8'
+    end
+
+    def arch
+      'archlinux'
+    end
+
+    def manjaro
+      'archlinux'
+    end
+
+    def zorin
+      'ubuntu_18.04'
+    end
+
+    def pop
+      'ubuntu_18.04'
+    end
+
+    def elementary
+      'ubuntu_18.04'
+    end
+
+    attr_reader :id, :version
+  end
+end

test/test_with_docker.rb

@@ -48,11 +48,19 @@ def test_with_ubuntu_22
   def test_with_archlinux
    test with: 'archlinux'
   end
-  
+
   def test_rockylinux_8
    test with: 'rockylinux_8'
   end
-
+
+  def test_amazonlinux_2
+   test with: 'amazon_2'
+  end
+
+  def test_amazonlinux_2022
+   test with: 'amazon_2022'
+  end
+
   def test_with_macos
    assert_equal(`bin/wkhtmltopdf --version`.strip, 'wkhtmltopdf 0.12.6 (with patched qt)') if macos?
   end

test/wkhtmltopdf/linux_os_detector_test.rb

@@ -0,0 +1,54 @@
+require 'minitest/autorun'
+require_relative '../../lib/wkhtmltopdf/linux_os_detector'
+
+module Wkhtmltopdf
+  class LinuxOsDetectorTest < Minitest::Test
+    {
+      ['ubuntu', '16.04'] => 'ubuntu_16.04',
+      ['ubuntu', '16.10'] => 'ubuntu_16.04',
+      ['ubuntu', '17.04'] => 'ubuntu_16.04',
+      ['ubuntu', '17.10'] => 'ubuntu_16.04',
+      ['ubuntu', '18.04'] => 'ubuntu_18.04',
+      ['ubuntu', '18.10'] => 'ubuntu_18.04',
+      ['ubuntu', '19.04'] => 'ubuntu_18.04',
+      ['ubuntu', '19.10'] => 'ubuntu_18.04',
+      ['ubuntu', '20.04'] => 'ubuntu_20.04',
+      ['ubuntu', '20.10'] => 'ubuntu_20.04',
+      ['ubuntu', '21.04'] => 'ubuntu_20.04',
+      ['ubuntu', '21.10'] => 'ubuntu_20.04',
+      ['ubuntu', '22.04'] => 'ubuntu_22.04',
+      ['ubuntu', '22.10'] => 'ubuntu_22.04',
+      ['linuxmint', '18.3'] => 'ubuntu_16.04',
+      ['linuxmint', '19.3'] => 'ubuntu_18.04',
+      ['linuxmint', '20.3'] => 'ubuntu_20.04',
+      ['linuxmint', '21.3'] => 'ubuntu_22.04',
+      ['debian', '9'] => 'debian_9',
+      ['debian', '10'] => 'debian_10',
+      ['amzn', '2018.03'] => 'centos_6',
+      ['amzn', '2'] => 'centos_7',
+      ['amzn', '2022'] => 'centos_7',
+      ['rocky', '8'] => 'centos_8',
+      ['rhel', '8.7'] => 'centos_8',
+      ['arch', 'xxx'] => 'archlinux',
+      ['manjaro', 'xxx'] => 'archlinux',
+      ['zorin', '16.2'] => 'ubuntu_18.04',
+      ['pop', '22.04'] => 'ubuntu_18.04',
+      ['elementary', '7.0'] => 'ubuntu_18.04',
+    }.each do |(id, version), base_os|
+      define_method "test_#{id}_#{version}" do
+        assert_equal base_os, LinuxOsDetector.new(id, version).os
+      end
+    end
+
+    def test_centos_6
+      detector = LinuxOsDetector.new('', '')
+      detector.instance_variable_set(:@extras, {'centos-release' => 'CentOS release 6.10 (Final)'})
+      assert_equal 'centos_6', detector.os
+    end
+
+    def test_unknown_returns_raw_os_and_version
+      assert_equal 'somelinux_10', LinuxOsDetector.new('somelinux', '10').os
+    end
+
+  end
+end